As an IGBT with low on-resistance, a trench gate type IGBT has widely been used. An IE (injection enhancement)-type IGBT has been developed, the IE-type IGBT enabling to use an IE effect because an active cell connected to an emitter electrode and an inactive cell region having a floating region are arranged alternately in a cell formation region. The IE effect serves to increase the concentration of charges accumulated in a drift region by preventing holes from being discharged from the emitter electrode side when the IGBT is in an on state.
Japanese Patent Application Laid-Open Publication No. 2012-256839 (Patent Document 1) discloses a technique in an IE-type trench gate IGBT in which each of linear unit cell regions provided in a cell formation region includes a linear active cell region and linear inactive cell regions provided so as to sandwich the linear active cell region from both sides thereof.
Japanese Patent Application Laid-Open Publication No. 2013-140885 (Patent Document 2) discloses a technique in an IE-type trench gate IGBT in which each of linear unit cell regions provided in a cell formation region includes first and second linear unit cell regions, in which the first linear unit cell region has a linear active cell region, and in which the second linear unit cell region has a linear hole collector cell region.
International Publication WO/2011/111500 (Patent Document 3) discloses a technique in an insulated gate semiconductor device in which one or more second trenches each formed to be between first trenches adjacent to each other and be parallel to the first trenches are formed, and in which a first conductor is buried in the second trench via an insulating film.